It said I needed baking soda (about a cup) and an essential oil like lavender. Honestly, I didn't have any essential oils (hangs head in shame, I know! I know!) but I did have a lemon! They get oils from the lemon rinds, right? Well, I went with that idea and just used my micro-grater and grated the yellow from the lemon and mixed it in. Whatever, it smelled good.
After mixing my concoction I sifted it onto the mattress and let it set for an hour then came back and vacuumed it up. Clean mattress! Right...At least it smelled good.